Asahi Kasei has developed a lithium pre-doping technology for high-voltage lithium-ion batteries with silicon-based anodes. The approach is intended to reduce first-cycle capacity loss while increasing energy density in cells for applications including electric vehicles (EVs).
Silicon-rich anodes can store more lithium than conventional graphite anodes, although some lithium is permanently consumed during the first charge-discharge cycle. Battery developers can compensate by adding more cathode active material, which increases material use and cell cost.
Asahi Kasei’s technology uses lithium carbonate as an additional lithium source. Special electrolyte additives lower the voltage required to decompose the lithium carbonate, allowing it to release lithium during the initial charge at voltages used in conventional lithium-ion cells.
The lithium carbonate is added to the cathode as a sacrificial lithium source. During the first charge, it decomposes and supplies lithium that compensates for losses associated with the silicon-containing anode.
In internal testing, Asahi Kasei used a nickel-manganese-cobalt (NMC) cell with an anode containing 90% graphite and 10% silicon monoxide (SiO). The company reported a 10% increase in energy density.
The process is designed to use relatively low-cost lithium carbonate and can be introduced without significant changes to existing battery manufacturing lines.
Asahi Kasei says the technology could also improve cycle life while reducing cost per Wh. The company expects the approach to be applicable across different cathode and anode material systems.
The company plans to conduct proof-of-concept evaluations with battery manufacturers and pursue licensing agreements as it moves the technology toward commercialization.
Filed Under: Batteries, Technology News